The present invention relates to a stackable container.
Patent Document 1 discloses a container stacking structure in which rectangular box-shaped plastic containers are stacked while being arranged in the same orientation by a column stacking method, and another container stacking structure in which containers are stacked while being arranged in different orientations by an interlock stacking method. The column stacking method refers to a method for vertically stacking containers while aligning the long sides and the short sides of each container stacked on top with the long sides and the short sides of the container below, respectively. In contrast, the interlock stacking method refers to a method for stacking containers in multiple layers while rotating the phase in the planer arrangement of each container stacked on top by 90 or 180 degrees relative to the container below.
The lower surface of the bottom wall of the container disclosed in Patent Document 1 has linear recesses that extend lengthwise and widthwise along the side edges of the bottom wall to form a lattice-like pattern. Thus, when containers are stacked by the column stacking method or the interlock stacking method, the upper edges of the container below are engaged with the linear recesses in the bottom wall of the container above, which restricts displacement between the containers.
Recently, to reduce the weight, containers have been used that are formed of hollow plastic plates made, for example, of corrugated plastic (for example, refer to Patent Document 2). The container disclosed in Patent Document 2 is formed by cutting a corrugated plastic into a cruciform plate including a rectangular bottom plate and side plates on the four sides of the bottom plate, folding the cruciform plate into a box shape, and attaching a reinforcing frame to the open end.